Persons that use present day systems to access a resource such as the telecommunications network, an automated teller machine, or some other similar resource, find that they must first verify their identity and then enter a command in order to obtain a desired service or action. Typically, these actions require three separate steps: (1) the user makes an identity claim; (2) that claim is verified; and (3) the user issues a command to the system. Verification of identity can itself be complicated, as systems today sometimes require a user to enter a large number of hard to remember digits, or to assert an identity and then provide some independent verification, such as a fingerprint, a retinal pattern, or a personal identification number (PIN). This is time consuming and often frustrating. The ideal arrangement would be to simply enable the identity of a user to be authenticated, and then permit that user to access a resource, all by simply uttering a single voice command. In the context of gaining access to a telecommunications network, in an ideal system, a caller would be able to simply say who he wanted to call, and the system would identify and verify the caller and then complete the call; the caller could thus simply say "Call Home", or some such similar phrase, and the call would be placed and charged to the correct and authorized account. The ideal arrangement, in the context of gaining access to an automated teller machine, would be to issue a voice command, such as "check balance", without having to enter a secret PIN or provide a physical input such as a fingerprint.
The type of true speaker identification capability described above is technologically unattainable at present, because the storage and data processing capacity that would be required to deal with voice samples received from a large number of potential access seekers does not exist, even in the largest distributed processing systems. A compromise, described in U.S. Pat. No. 5,127,043 issued to Hunt et al. on Jun. 30, 1992, employs speaker independent voice recognition to identify who the caller purports to be, and then speaker dependent processing to verify that the characteristics of that caller's voice sample match those stored for the purported caller. This means that a caller can speak a series of digits serving as the identity claim and verification phrase, and then speak a command. Because a user must still speak his or her number, and that number must be appropriately recognized and processed before the user can then speak additional commands, the goal of saying "Call Home" without explicit entry of an identity claim and without performing a verification step, is thus still not attainable at the present time. Another approach, also in the context of a telecommunications system, is described in U.S. Pat. No. 5,181,237, issued to Dowden et al. on Jan. 19, 1993. In that patent, customers are assigned specific individual telephone numbers which, when dialed are routed to a switching system containing prerecorded phrases in the voice of that customer. These phrases might be phrases such as "Mom", "Broker", "Home", "Secretary", and so on, each having an associated stored telephone number. When the customer dials his or her personal number, the call is connected to the switching system, and the prerecorded phrases for that customer are retrieved, so that a command issued by the customer can be matched against the stored phrases. If there is a match, the recognized command is executed by completing the call to the stored number associated with the command. In this way, a customer can simply call the system and say "Call Home". While the Dowden approach thus has certain advantages it does not address the question of security or access control, which is necessary to avoid access by unauthorized individuals.